A semiconductor product is produced through the steps of forming a photosensitive resin as an etching resist on a silicon wafer and subjecting the silicon wafer to etching, and the like steps.
This photosensitive resin is liquid, and is applied onto a surface of the silicon wafer, using a spin coater and the like. After the application, the resin has to be dried. Thus, the silicon wafer subjected to the application process is put on a heater and heated.
Hitherto, as a heater made of metal and used for such a purpose, a heater wherein heating elements are arranged on the back surface of an aluminum plate is adopted.